The transfer case in modern vehicles selectively provides power flow or drive torque to the front and rear drive axles of many vehicles for four wheel drive operation and improved vehicle handling and stability. Such transfer cases generally provide an additional gear reduction when placed in low range particularly useful when difficult or off--road conditions occur are encountered.
Prior to the present invention various manual controls have been employed to select and control the operating ranges of automatic transmissions and associated transfer cases drivingly connected to the front and rear drive wheels of wheeled automotive vehicles. Among such controls are a wide range of console mounted transmission range selector levers and associated transfer case levers mounted adjacent to one another. These separate levers have associated operating linkages connected to the associated transmission and transfer cases for moving controls for effecting the selection of the gear ratios of the transmissions and the operation ranges provided by the gearing of the transfer cases.
In the event the transfer case gearing is electronically controlled, external switches such multi-position rotary and rocker type selector switches mounted on the instrument panel are manually pushed, gripped and turned or toggled to operate controls for an electric motor operatively connected to a shift mechanism in the transfer case. Activation of the shift mechanism shifts the transfer gearing between selected operations such as between 4-wheel low, 4-wheel high or to a neutral condition.
While these prior constructions have provided useful and effective control of transmissions and their transfer cases for four wheel drive operation, they generally involve discrete external switching devices that must be located by the operator and physically touched and closed to effect transfer case gear changes.
In other electronic controlled transfer cases multiple switches, complex controls and complicated gate patterns for establishing selector lever movements are employed to effect transmission and transfer gear operations.